I have a project that has Python requirements in the root plus a VuePress documentation site with package.json. Netlify deployment tries (unnecessarily) to install the Python requirements (and fails, so the whole deployment fails) but I’d only want it to install and build VuePress. Is there any other way to do this other than moving the package.json into a different directory?

In other words, I’d like to tell Netlify build to only install JS dependencies and forget about the rest of the repo.

If all your dependency files are in the same directory then there is no way to prevent us from attempting to install all of them. I recommend that you have the different projects in different directories. If your VuePress site doesn’t depend on your python code, move it to a sub-directory and then set a base directory in your netlify.toml, or build settings in the UI. That way we’ll only look in your base directory and install the modules in your package.json there instead of installing the dependencies from your requirements.txt in the root in addition to the package.json.